Method and system for shaped glasses and viewing 3d images

ABSTRACT

Shaped glasses have curved surface lenses and spectrally complementary filters disposed on the curved surface lenses configured to compensate for wavelength shifts occurring due to viewing angles and other sources. The spectrally complementary filters include guard bands to prevent crosstalk between spectrally complementary portions of a 3D image viewed through the shaped glasses. In one embodiment, the spectrally complementary filters are disposed on the curved lenses with increasing layer thickness towards edges of the lenses. The projected complementary images may also be pre-shifted to compensate for subsequent wavelength shifts occurring while viewing the images.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/801,574 filed on May 9, 2007, hereby incorporated by reference in itsentirety.

COPYRIGHT NOTICE

A portion of the disclosure of this patent document contains materialwhich is subject to copyright protection. The copyright owner has noobjection to the facsimile reproduction by anyone of the patent documentor the patent disclosure, as it appears in the Patent and TrademarkOffice patent file or records, but otherwise reserves all copyrightrights whatsoever.

BACKGROUND OF THE INVENTION

1. Field of Invention

The present invention relates viewing systems and products for viewingspectrally separated 3D images. The invention is also related to viewingsystems used in a Digital Cinema (D-Cinema) Theatre and improves currentmethods for projecting a 3D stereoscopic movie.

2. Discussion of Background

Methods for 3D stereoscopic projection include Anaglyph, LinearPolarization, Circular Polarization, Shutter Glasses, and SpectralSeparation. Anaglyph is the oldest technology, and provides left/righteye separation by filtering the light through a two color filter,commonly red for one eye, and cyan for the other eye. At the projector,the left eye image is (commonly) filtered through a red filter, and theright image filtered through a cyan filter. The eyewear consists of ared filter for the left eye, and a cyan filter for the right eye. Thismethod works best for black and white original images, and is not wellsuited for color images.

Linear Polarization 3D provides separation at the projector by filteringthe left eye through a linear polarizer (commonly) oriented vertically,and filtering the right eye image through a linear polarizer orientedhorizontally. The eyewear consists of a vertically oriented linearpolarizer for the left eye and a horizontally oriented polarizer for theright eye. The projection screen must be of the polarization preservingtype, commonly referred to as a “silver screen” because of itsdistinctive color. Linear Polarization allows a full color image to bedisplayed with little color distortion. It has several problems, theseinclude the need for a silver screen which is expensive, fragile, andnot uniform. Another problem is that the viewer must keep his headoriented vertically to avoid crosstalk from one eye to another.

Circular Polarization 3D was invented to address the problem ofrequiring the viewer to keep his head oriented vertically. CircularPolarization provides separation at the projector by filtering the lefteye image through a (commonly) left handed circular polarizer, andfiltering the right eye image through a right handed circular polarizer.The eyewear consists of a left handed circular polarizer for the lefteye and a right handed circular polarizer for the right eye. A silverscreen is also needed for this approach.

Shutter Glasses provides separation by multiplexing the left and rightimages in time. A filter for separation at the projector is notrequired. The eyewear consists of Shutter Glasses. These are activeglasses that electronically shutter the lens in synchrony with theprojector frame rate. The left eye image is first displayed, followed bythe right eye image etc. Since having a direct wired connection to theGlasses in a theatre is impractical, a wireless or infrared signalingmethod is used to provide a timing reference for the left/right eyeshuttering. This method requires an IR or RF transmitter in theauditorium. The Shutter Glasses are expensive and hard to clean, requirebatteries that must be frequently replaced, and are limited in theirswitching rate. Shutter glasses are only practical for use with D-Cinemaor other electronic projection systems since very few film projectorsprovide the signal required to synchronize the shutter glasses with theframe rate. The method does not require a silver screen.

Spectral Separation provides separation at the projector by filteringthe left and right eye spectrally. The system differs from anaglyph inthat the filters for the left and right eye each pass a portion of thered, green, and blue spectrum, providing for a full color image. Theband pass spectrum of the left eye filter is complementary to the bandpass spectrum of the right eye filter. The eyewear consists of filterswith the same general spectral characteristics as are used in theprojector. While this method provides a full color image, it requirescolor compensation to make the colors in the left and right eye matchthe colors that were present in the original image, and there is a smallreduction in the color gamut compared to the gamut of the projector.

All of the above methods for providing left/right eye separation for a3D Stereoscopic presentation can be used with either two projectors (onefor the left eye and one for the right eye), or may be used with asingle D-Cinema projector system. In the dual projection system, theprojection filter is usually static, and is located in front of theprojection lens. In a single D-Cinema projector system, the left andright images are time multiplexed. Except for the Shutter Glasses casewhere no projection filters are required, this means that the projectionfilters must change at the L/R multiplex frequency. This can be donewith either a filter wheel in the projector synchronized to themultiplex frequency, or with an electronically switched filter.

SUMMARY OF THE INVENTION

The present inventors have realized the need for improvements inspectrally separated viewing devices and systems. The invention providesseveral techniques to remove and compensate for blue shift that occurswhen viewing images through filters at off-axis (other than normal)angles. The blue shift is undesirable because it can result in crosstalkbetween left and right images in a 3D image presentation.

Generally described, in one embodiment, the present invention provides apair of 3D spectral separation filters (eye filters), disposed on leftand right lenses of a pair of viewing glasses, the eye filterscomprising a combination of increased (and proportional to wavelength)guard bands, and appropriately curved lenses to reduce crosstalk, colorshift, and reflections at the edge of the field of view. A blue shiftedcolor filter in a projector that projects images for viewing through theglasses may also be utilized. Although the present invention encompassesa combination of improvements to viewing glasses and preparation ofimages for viewing (e.g., image projection), the invention may bepracticed with less than all the improvements in combination.

In one embodiment, the present invention provides spectral separationviewing glasses, comprising, a first lens having a first spectralfilter, and a second lens having a second spectral filter complementaryto the first spectral filter, wherein the first lens and the second lensare each curved to reduce the wavelength shift that occurs when viewingan image at other than an angle normal to a filter through which theimage is being viewed. An amount of curvature of the lenses (and hencethe filters) is calculated such that viewing angles across a viewingscreen are closer to normal angles through the lenses. The curvature isimplemented, for example, as a spherical curve.

In another embodiment, the invention is embodied as spectral separationviewing glasses, comprising, a first lens comprising a first spectralfilter, and a second lens comprising a second spectral filtercomplementary to the first spectral filter, wherein the first spectralfilter and the second spectral filter have at least one guard bandbetween adjacent portions of spectrum of the spectral filters. The guardband has a bandwidth sufficient to remove crosstalk of spectrallyseparated images viewed through the glasses, and, for example, iscalculated based on an amount of wavelength shift occurring when viewingportions of the spectrally separated images at an angle through thefilters.

In one embodiment, the present invention provides a spectral separationviewing system, comprising, viewing glasses having both curved lensesand increased guard bands, and a projection system configured to projectfirst and second spectrally separated images wherein the images arewavelength pre-shifted to compensate for wavelength shifts occurringduring display and/or viewing of the images. Such systems are preferablyimplemented in a commercial movie theater, but are also applicable tolarge screen televisions, computers, virtual reality systems, and otherdisplay devices.

The present invention includes a method, comprising the steps of,projecting first and second spectrally separated images onto a displayscreen, viewing the projected images through a pair of glasses having afirst lens having a first spectral filter matching the first spectrallyseparated image and a second lens having a second spectral filtermatching the second spectrally separated image, wherein the spectralfilters are configured to have a varying amount of wavelength shifteffect depending upon a viewing angle through the lens.

In one embodiment, the present invention is a 3D viewing system,comprising, means for projecting spectrally separated images, means forviewing the spectrally separated images through different ocularchannels, and means for compensating for wavelength shifts occurring dueto viewing angles to portions of the images. The means for compensatingmay include, for example, means for adjusting an amount of spectralfiltering performed on different portions of the image based on viewingangle. The means for compensating includes, for example, means forproducing a wavelength mismatch between projector filters and eyefilters that compensates for an amount of wavelength shift that occursin the eye filters due to viewing angle.

The present invention may also be described as shaped glasses,comprising a pair of spectrally complementary filters disposed on curvedlenses of the glasses. The spectrally complementary filters may includeguard bands between adjacent spectrums of the spectrally complementaryfilters. In one embodiment, the thickness of dielectric layers of thespectrally complementary filters increases toward edges of the lenses.

The present invention includes a method, comprising the steps of,distributing shaped glasses to audience viewers, and projecting firstand second spectrally complementary images on a display screen withinview of the audience members, wherein the shaped glasses comprise firstand second shaped lenses having first and second spectrallycomplementary filters respectively disposed thereon. In one embodiment,the first and second spectrally complementary filters respectivelycorrespond in bandwidth to the projected first and second spectrallycomplementary images. However, the filters are not necessarily requiredto correspond exactly with the projected images of the filters. Theshaped glasses comprise, for example, spherically shaped lenses.

The present invention includes a storage medium having at least a visualperformance stored thereon, that, when loaded into a media playercoupled to a display device, causes the media player to transmit thevisual performance for display to the display device; wherein the visualperformance as displayed on the display device is configured for viewingthrough a pair of shaped glasses. The storage medium is, for example,prepackaged with at least one pair of shaped glasses and available forpurchase via a retail outlet.

In yet another embodiment, the present invention is a system for viewing3D images, comprising, serving 3D content over a network to a receivingelectronic device, and displaying the 3D content, wherein the 3D contentcomprises spectrally complementary images intended to be viewed withspectrally separated shaped glasses. The receiving electronic device is,for example, a display system located at a movie theater.

Portions of the invention may be conveniently implemented in programmingon a general purpose computer, or networked computers, and the resultsmay be displayed on an output device connected to any of the generalpurpose, networked computers, or transmitted to a remote device foroutput or display. In particular, the invention includes the utilizationof software that implements color processing separately on each ocularchannel. Any components of the present invention represented in acomputer program, data sequences, and/or control signals may be embodiedas an electronic signal broadcast (or transmitted) at any frequency inany medium including, but not limited to, wireless broadcasts, andtransmissions over copper wire(s), fiber optic cable(s), and co-axialcable(s), etc.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the invention and many of the attendantadvantages thereof will be readily obtained as the same becomes betterunderstood by reference to the following detailed description whenconsidered in connection with the accompanying drawings, wherein:

FIG. 1A is an illustration of viewing angles;

FIG. 1B is graph illustrating spectrum of left projector filter andright eye filter;

FIG. 2 is a graph illustrating spectrum of left projector filter vs.blue shifted right eye filter;

FIG. 3 is a graph illustrating spectrum of blue shifted left projectorfilter vs. blue shifted right eye filter;

FIG. 4A is a diagram illustrating geometry of curved lenses centered ata viewer's pupil;

FIG. 4B is an illustration of glasses with spherical lenses;

FIG. 5 is a diagram illustrating geometry of curved lenses and showingchild interpupillary distances;

FIG. 6 is a diagram illustrating geometry of curved lenses for 20 degreeangle at an edge of the lenses;

FIG. 7 is a diagram illustrating geometry of curved lenses withnon-spherical curve;

FIG. 8A is a diagram illustrating effect of lens curvature on lightcoming from behind a viewer;

FIG. 8B is a drawing of dihedral angles for a pair of viewing glasses.

FIG. 9 is a drawing illustrating glass frames configured for use ondifferent sized heads; and

FIG. 10 is a diagram illustrating geometry of optimized dihedralglasses.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

This invention addresses some of the problems with the SpectralSeparation method for projecting 3D images, specifically this inventionaims to improve the off-axis filter characteristics when thin filmdielectric (interference) filters (e.g., right eye and left eye filters)are used to implement eyewear (e.g., glasses) for viewing spectrallyseparated images.

When light passes through an interference filter at a non-normal angle,the filter characteristics (response shapes, not to be confused with thephysical shape of the filter) are changed, and the entire spectralfilter response is shifted toward shorter wavelengths (toward the blue).The filter characteristic response shapes are also adversely affected atlarger angles. This is a fundamental attribute of interference filters,and can be compensated for by designing the filter for a specific angleif all of the rays are parallel. In cases where the light bundle is notparallel, as in the case with the use of 3-D glasses, solutionsinvolving only design of the filter characteristics are less practical.

Glasses currently used for spectral separation consist of flatinterference filters located about 2 cm in front of the viewer's eyes.In a 3D Cinema theatre (e.g., 3D D-Cinema) the light from the screendoes not pass through the interference filters at a single angle. For aviewer located center and one screen width back, when viewing the imageat the center of the screen, the light from the center of the screenwould pass through the interference filters of the glasses at a normal(perpendicular) angle (assuming the viewer's head is positioned suchthat the plane of the interference filters is parallel to the plane ofthe screen). Under similar conditions, light from the edge of the screenwould pass through the interference filters at an angle of about 26degrees.

This viewing position is reasonably close to the screen, but is notabnormal; many of the seats in a common auditorium are located closer,and angles of 40 degrees are possible. A 26 degree angle from the edgeof the screen would have the effect of shifting the filter responsetoward the blue by about 14 nanometers (nm), and would somewhat distortthe filter shape. The resulting 3D image appears to have noticeablecolor shift and increased left/right eye crosstalk towards the edges ofthe screen.

The invention uses a combination of several techniques to reduce theeffects of the blue shift, and to reduce the blue shift occurring fromnon-normal viewing angles. It should be remembered that the blue shiftat the interference filters (e.g., lenses of the glasses having filtersdisposed thereon) is primarily important because it causes a mismatchbetween spectral characteristics of the projector filter (e.g., a filterwheel or electronically switched filter) and the glasses, or moreprecisely, a mismatch between the spectra of light forming the images(from whatever source) and the characteristics of the glasses at a givenviewing angle.

Referring now to the drawings, wherein like reference numerals designateidentical or corresponding parts, and more particularly to FIG. 1Athereof, there are illustrated example viewing angles through glasses1110 for a viewer 1100 of an image projected onto a movie screen 1120.

The viewing angles range from normal to somewhat oblique (e.g.,approximately θ₁ to θ₃, respectively). The glasses 1110 include lenseswith dielectric based interference filters. The non-normal viewingangles have an amount of blue-shift associated with the viewed imagethat increases with greater obliqueness of the viewing angle through theinterference filters. For example, light entering the user's eyes fromthe more oblique angles θ₂ and θ₃ will be shifted toward bluewavelengths whereas the more normal angle θ₁ will have little, if any,blue shift. The blue shift, or wavelength shift, so described resultsfrom a shift in the interference filter properties such that the lightbands passed by the filter are shifted toward shorter wavelengths.

One effect of the blue shift of light viewed at the edge of the screen(e.g., light 1130) is to introduce crosstalk in the image. This can bereduced by increasing the guard bands between left eye and right eyefilter characteristics. FIG. 1B illustrates characteristics of exemplaryfilters used for 3D spectral separation. As shown in FIG. 1B, bandwidthsfor a left projection filter 100, and a right eye filter 110, includesguard bands 120, 122, 124, 126, and 128 which appear as notches betweenadjacent light bands (FIG. 1B illustrates the right eye filter and theleft projection filter; the right eye filter approximately representsbandwidths of the right projection filter and the left projection filterapproximately represents bandwidths of the left eye filter). Byincreasing the width of the notch (or guard band) between left and rightspectra in both the eye filters and the corresponding projector filters,crosstalk can be reduced. This also reduces the perceived color shift.This method also reduces the optical efficiency of the system, but thistradeoff may be made.

As can be seen in FIG. 1B, as a pair, the left and right eye filters arecomplementary in that the filter properties of the left eye filter(approximately represented by the left projection filter 100) complementthe filter properties of the right eye filter 110. It is not a fullcomplement in that the guard bands keep the combined filters frompassing the entire portion of the spectrum between the longest andshortest wavelengths passed by the filters. Further, additionaldifferences in bandwidth within the ranges of the various bands passedby the filters may be made so as to accommodate engineering decisionsregarding color space issues that need to be addressed for a particularapplication.

Another approach is to pre-blue shift characteristics of the projectorfilter, or red shift the eye filters, such that for viewing at a normalangle of incidence through the eye filters, the filter characteristicsare red shifted with respect to the projector filter. This increases thecrosstalk and color shift for normal (on axis) viewing, but this can betuned such that for on axis viewing the crosstalk and color shift is notobjectionable. For the off axis case, the performance is improved sincethe difference between the projector filters and the blue shifted(off-axis) eye filters is lower.

FIG. 2 and FIG. 3 describe this situation. As shown in FIG. 2, a leftprojector filter 200, and a blue shifted right eye filter 210 have guardbands including guard band 220 separating adjacent bands of light). Asshown in FIG. 3, a blue shifted left projector filter 300 and a blueshifted right eye filter 310 have guard bands including guard band 320separating adjacent bands of light. As seen by comparing FIG. 2 and FIG.3, the notch (guard bands 210 and 310) separating the adjacent bands oflight is larger in FIG. 3.

Applying this to the case described earlier, the shift of 14 nm at theedges of the screen could be reduced to an effective shift of 11 nm ifthe projector filter were shifted blue 3 nm. There would be a “redshift” of 3 nm at the center of the screen.

Another approach is to curve the filters, which can be implemented, forexample, by disposing the eye filters on curved lenses of viewingglasses. This has the advantage that it has the potential of actuallyreducing the blue shift.

FIG. 4A describes the geometry of curved lenses with a radius centeredat the eye pupil. The lenses shown (lens 405A having optical axis 410Aand lens 405B having optical axis 410B) have a width of 50 mm and thechord is located 20 mm from a respective pupil (and center of curvature)(e.g., 400A and 400B). The measurements were made for the inventor'seyes, but are representative of the general situation that could beimplemented for anyone wearing 3D glasses. Using glasses with lenseshaving a spherical section with a radius centered on the entrance pupilof the eye virtually eliminates any blue shift in the filters becausethe light passes through the lenses (and hence, the filters) virtuallynormal to the lens/filter for viewing all parts of the screen. Somedistortion occurs when the viewer turns his eyes to look at differentparts of the screen, but for the geometry shown, this is notsignificant. FIG. 4B illustrates two views of a pair of glasses 490having curved lenses 492A and 492B which are both spherically shaped andhaving spectrally complementary dielectric filters disposed thereon(left eye filter 496A and right eye filter 496B).

The curvatures of the lenses so implemented are distinguished fromprescription glasses in that the implemented curvatures are not tocorrect vision. Nevertheless, in one embodiment, the curvature of theinvention may be implemented over or in addition to other lenscharacteristics intended to fulfill a viewer's prescription needs.

The curved lens solution still has some limitations. First, the radiusof curvature of 30 mm resulting from the geometry described aboveappears very “bug-eyed,” and would be esthetically unpleasing. Second,this curvature would produce glasses whose weight would be centered wellin front of the nosepiece, and they would be poorly balanced. Third,this radius may be too short to allow uniform coating of an interferencefilter.

Fourth, the interpupillary distance of eyes varies significantly, andthis would mean that glasses designed for the mean would be improperlycurved for someone with other than the mean distance. For example, witha child the situation may result in an angle of about 10 degrees forviewing of the center of the screen. As shown in FIG. 5, the location ofa child's pupils (510A and 510B) and the resulting optical axis of thechild's eye (530A and 530B) is displaced off the corresponding opticalaxis of the glasses (520A and 520B respectively centered at center ofcurvatures 500A and 500B).

Even considering the limitations associated with curving the lensesand/or filters, this technique is valuable. Although in general cases orproductions for mass audiences, it may not make sense to attempt to havethe radius of curvature centered directly at the entrance pupil of theeye. By making the lenses spherical but with a radius of curvaturecentered behind the entrance of the pupil of the eye, much of theproblems are removed (e.g., bringing the center of gravity back towardthe viewer, and a less “bug-eyed” appearance) and the advantages aresignificantly retained.

In one alternative, the lenses may use a non-spherical curvature, suchas a cylindrical curvature where the lenses are only curved from left toright, and there is no curvature in the vertical direction. This ispossible because the screens always have an aspect ratio such that thehorizontal extent (e.g., width) is about twice the vertical extent(e.g., height). Another alternative is to use a curvature that is nonspherical in either direction, such as a multiple radius surface, or onethat follows a specific mathematical function. These have advantages forallowing a greater interpupillary variation. An additional advantage ofcurved lenses includes the reduction of reflections from bright surfacesbehind the viewer, since these reflections are not directed toward theeye.

A final approach involves the design of the interference filters. Thisapproach requires changing the thickness of the dielectric layers as afunction of the distance from the center of each eye filter. If thethicknesses of the dielectric layers are increased at the edges of thefilters such that they cause a red shift in the filter characteristics,this can be used to compensate for the blue shift caused by the anglechange at the edges of the field of view through the filters.

If the filters are implemented on flat glass, the thickening of thedielectric layers may increase manufacturing costs due to difficulty inimplementing the increased thicknesses at different points on the flatglass. However, when coating on a curved surface, some thickening occursduring the coating process. This approach therefore becomes a practicaladjunct to the curved lens solution.

The best method for achieving high performance with interference filtersincorporates the four techniques described above in the followingmanner. First, the guard bands between left and right eye filters shouldbe greater than approximately 2% (e.g., 2.2%) of the wavelength of thatfilter band. For example, for a filter with a left/right crossover at640 nm, the guard band should be approximately 14 nm. Second, theprojector filter should be designed to be blue shifted (with respect tothe eye glass filters) greater than 0.6% of the wavelength of the filterband. In the same example, the center of the guard band for theprojector filter would be 640−3.8=636.2 nm. The combination of theseallow nominally manufactured lenses and eye filters (when used with anominally manufactured projector lens and projector filters) to betilted such that a blue shift of 18 nm occurs before serious degradationof the image occurs.

However, the combined manufacturing tolerance from the projector filtersand the eye filters reduces this to about 9 nm. The 9 nm guard band thatremains can be used for accommodating the blue shift caused by the lightgoing through the left and right eye filters at an angle. The anglethrough the left and right eye filters that causes a 9 nm shift is about20 degrees. If the curvature of the eye filters (e.g., curvature oflenses upon which the eye filters are disposed or incorporated) isadjusted to allow the light from the edge of the eye filters to passthrough to the eye at a maximum of 20 degrees relative to the normal ofthe eye filters at the edge, then serious degradation of the image atthe edge of the eye filters will not occur.

For a simple sphere, and with the eye looking straight at the center ofthe screen (e.g., a primary gaze normal to a tangent of the lens), theradius of curvature needed to achieve this is approximately 50 mm. Asshown in FIG. 6 (lenses 605A and 605B have respective centers ofcurvature 610A and 610B; adult pupil locations at 615A, 615B andcorresponding optical axis of the lenses and adult eye 630A and 630B;child pupil locations at 620A, 620B and corresponding optical axis ofchild's eye 635A and 635B). In practice the radius of curvature may besomewhat greater than 50 mm to accommodate the pupil shift when the eyeis turned to observe the side of the picture screen.

Although spherically shaped lenses are preferred, non-spherical lensesdo have some advantages. FIG. 7 shows left and right lenses 705A and705B with a non-spherical curve (adult pupils 700A, 700B; optical axisof the lenses 715A, 715B; child pupils 710A, 710B, and correspondingoptical axis of child's eye 720A, 720B). The left and right lensesincorporate corresponding left and right eye filters. The filters are,for example, disposed on one or more surfaces of the lenses. Theadvantages of a non-spherical curve are found in accommodatingvariations of interpupillary distances between different viewers.Finally, a non-uniform dielectric coating can be used to red shift thefilter characteristics at the edges of the filters, further improvingthe performance.

A more important advantage is that reflections from behind the viewerare reduced by the curvature. This is important because the interferencefilters disposed on the eyeglass lenses reflect light that is nottransmitted, and are therefore quite reflective. Without the curve, theaudience behind the viewer is visible across much of the back side ofthe lens. With the curve, only a portion (or none) of the lens has areflection from behind the viewer. FIG. 8 illustrates this advantage bycomparison of a curved lens 705 having a center of curvature at 708 anda flat lens 710. With respect to the flat lens 710, a relatively wideangled light ray 725 from behind the viewer is reflected off the flatlens into the viewer's pupil 700A. With respect to the curved lens 705,it is shown that only a relatively narrow angle (light ray 720) canreach the viewer's pupil 700B via reflection from the curved lens. Inaddition, the viewer's temple 730 blocks most light rays sufficientlynarrow to enter the viewer's temple.

Further optimization of the techniques discussed can be achieved byaccommodating interpupillary distance variation among the population. Ingeneral, interpupillary spacing is directly related to head width andgirth. Adults have larger width and girth, and wider interpupillaryspacing, while children are smaller in these dimensions. Ideally, aviewer would wear glasses with the left and right eye filters disposedon corresponding left and right lenses of the glasses where theinterocular spacing of the lenses is optimized for the viewer'sparticular interpupillary distances.

In a theatre or other large volume application, it is cumbersome tostock different sized glasses. As an optimization to the curved glassesit is possible to incorporate a feature into the design of the frame ofthe glasses that automatically adjusts a dihedral angle between thecurved lenses to accommodate wider and narrower interpupillary spacing.Adjusting the dihedral angle insures a close to normal light incidencewhen viewing the screen with a primary gaze. This adjustment is done byexploiting the flexibility and bending strength properties of moldedthermoplastic frames, or other frames having similar properties ofstrength and flexibility (e.g., metals, fiberglass, composites, etc).

In this design there is an outward convexity to the shape of the frames,which creates a dihedral angle between the lenses. In one embodiment,the bridge of the glasses is designed to flex slightly with head sizevariation due to pressure on the frame (e.g., pressure exerted on thetemple portion of the frames). This flexing results in dihedral anglechanges. As shown in FIG. 8B, wider heads 875 with (statistically)larger interpupillary spacing have a larger dihedral angle Ø_(A). Inthis context, the dihedral angle is defined as the angle between aplanes extending through endpoints on opposite ends of the lenses (seedashed line in FIG. 8B). Smaller heads 880 would have a smaller dihedralangle θ_(B). With a smaller head and corresponding smaller dihedralangle between the lenses, the distance between the forward directedradii of the curved lenses is reduced to more closely match the smallerinterpupillary spacing.

FIG. 9 illustrates both cases. Glasses 900 are illustrated in a firstposition 900A as when worn by an adult with a relatively larger sizedhead. Interpupillary spacing of the adult is represented by Y. A templeor “around the ear” portion of the frame of the glasses have a spacingrepresented by Y' to accommodate the adult's head size, causing a flexof the bridge 910 of the glasses and resulting in a larger dihedralangle between the lenses.

Position 900B, is similar to that when worn by a child with a relativelysmaller sized head, and the interpupillary distance of the child isrepresented by X. The bridge 910 is less flexed because the temple or“around the ear” spacing is reduced to X' which results in a smallerdihedral angle between the lenses. The smaller dihedral angleaccommodates the child's smaller interpupillary spacing as describedabove.

FIG. 10 illustrates details for the lenses. At 1005, an adult right eyepupil 1010A is shown relative to a child's eye pupil 1015A), with thelens 1020 having a center of curvature at 1025A. As seen in FIG. 10,comparing the position of lens 1020 to lens 1030 in position 1030A, alarger dihedral exists between the lenses. This is the appropriate lensconfiguration for an adult.

When worn by a child (or person with a relatively smaller sized head),an amount of flex of the bridge of the glasses cause lenses 1030 and1020 to decrease in dihedral as illustrated by 1050 for the left eye(consistent with FIG. 9, a similar dihedral decrease (not shown) occursfor the right eye in lens 1020). The center of the radius of curvature(1040 for lens 1030 in position 1030B) has shifted from an alignmentcorresponding to the adult pupil 1010B to an alignment corresponding tothe child's pupil 1015B.

FIGS. 8B, 9, and 10 are illustrative of an accommodation for both “adultsized” and “child sized” heads and interpupillary distances. However, itshould be understood that interpupillary distances and head sizes varyamongst the entire population. While near perfect alignment may occurfor some viewers, it is not required and the embodiments illustratedfunction to accommodate the varying head sizes and interpupillarydistances by improving the viewing angle alignments in most cases.

The lenses shown in FIG. 10 have a 50 mm radius of curvature and thedihedral angle is 2 degrees. With conventional sized frames the dihedralangle change for the average adult verses child is about 5 degrees(approximately 2.5 degrees accounted for on each side of the frames fora total of about 5 degrees). This technique works best with lenses witha radius of curvature that is about half the length of the templeportion of the glasses.

In describing preferred embodiments of the present invention illustratedin the drawings, specific terminology is employed for the sake ofclarity. However, the present invention is not intended to be limited tothe specific terminology so selected, and it is to be understood thateach specific element includes all technical equivalents which operatein a similar manner.

For example, when describing a dielectric layer, any other material usedas filter and exhibiting a substantive wavelength shift (e.g.,nano-material coatings), whether used alone or in combination withothers so as to have an equivalent function or capability, whether ornot listed herein, may be substituted therewith. In another example, aflexible bridge piece may be substituted with any mechanism suitable toadjust a dihedral angle of the lens, including a ratchet mechanism,spring loaded stops, etc.

In yet another example, lenses according to the present invention may beconstructed of glass, plastic, or any other such material providing theappropriate shapes as described above.

Furthermore, the inventors recognize that newly developed technologiesnot now known but having a similar structure or functionality may alsobe substituted for the described parts and still not depart from thescope of the present invention. All other described items, including,but not limited to lenses, layers, filters, wheels, screens, displaydevices, etc should also be considered in light of any and all availableequivalents.

Portions of the present invention may be conveniently implemented usinga conventional general purpose or a specialized digital computer ormicroprocessor programmed according to the teachings of the presentdisclosure, as will be apparent to those skilled in the computer art(e.g., controlling an electronically switched pre-blue shift projectionfilter).

The present invention includes a computer program product which is astorage medium (media) that includes, but is not limited to, any type ofdisk including floppy disks, mini disks (MD's), optical discs, DVD,HD-DVD, Blue-ray, CD-ROMS, micro-drive, and magneto-optical disks, ROMs,RAMs, EPROMs, EEPROMs, DRAMs, VRAMs, flash memory devices (includingflash cards, memory sticks), magnetic or optical cards, SIM cards, MEMS,nanosystems (including molecular memory ICs), RAID devices, remote datastorage/archive/warehousing, or any type of media or device suitable forstoring instructions and/or data. The present invention includessoftware for controlling aspects of the present invention including, forexample, switching of pre-blue shifted filters or performance of colorcorrection stored on any computer readable medium (media).

In addition, such media may include or exclusively contain contentprepared or ready for display according to the present invention. Suchcontent is, for example, read from the media and then transmittedelectronically over a network, broadcast over the air, or transmitted bywire, cable or any other mechanism. Ultimately, the content of suchmedia may be provided to a display device and then viewed in accordancewith one or more aspects of the invention. The content is, for example,prepared or optimized so as to project images having bandwidthsoptimized for the display and viewing processes described herein. Suchmedia may also be packaged with glasses and/or filters preparedaccording to one or more of the various aspects of the invention asdescribed above.

The present invention may suitably comprise, consist of, or consistessentially of, any of element (the various parts or features of theinvention, e.g., shaped lenses, varying dielectric layer thicknesses,pre-shifting projected or displayed images, etc., and/or anyequivalents. Further, the present invention illustratively disclosedherein may be practiced in the absence of any element, whether or notspecifically disclosed herein. Obviously, numerous modifications andvariations of the present invention are possible in light of the aboveteachings. It is therefore to be understood that within the scope of theappended claims, the invention may be practiced otherwise than asspecifically described herein.

1. 3D viewing glasses comprising a first lens configured to pass a firstset of wavelengths and a second lens configured to pass a second set ofwavelengths wherein the wavelength sets passed by the lenses compriseboth specific wavelengths intended to carry image content from a displaydevice to the glasses and wavelengths shifted from the specificwavelengths wherein the shifted wavelengths are wavelengths that areshifted when passing through at least one of the lenses at an angle. 2.The 3D viewing glasses according to claim 1, wherein the shiftedwavelengths comprise wavelengths shifted by a 20 degree angle passagethrough one of the lenses.
 3. The 3D viewing glasses according to claim1, wherein a curvature of the lenses is sufficient to cause wavelengthsfrom a display screen to be incident and/or pass the lenses at a maximumof approximately 20 degrees to a normal of the lens surface.
 4. The 3Dviewing glasses according to claim 1, wherein the specific wavelengthscomprise at least some of the wavelengths emitted by a Dolby 3D cinemaprojection system.
 5. The 3D viewing glasses according to claim 1,wherein the first set of wavelengths are passed via a first set ofpassbands that comprise passbands of approximately 425 nm to 455 nm, 490nm to 530 nm, and 575 nm to 630 nm.
 6. The 3D viewing glasses accordingto claim 5, wherein the second set of wavelengths are passed via asecond set of passbands that comprise passbands of approximately 460 nmto 475 nm, 540 nm to 570 nm, and 640 nm to 690 nm.
 7. The 3D viewingsystem according to claim 1, wherein the first set of wavelengths arepassed via a first set of passbands consisting of passbands ofapproximately 425 nm to 455 nm, 490 nm to 530 nm, and 575 nm to 630 nm.8. The 3D viewing glasses according to claim 7, wherein the second setof wavelengths are passed via a second set of passbands consisting ofpassbands of approximately 460 nm to 475 nm, 540 nm to 570 nm, and 640nm to 690 nm.
 9. The 3D viewing glasses according to claim 1, whereinthe lenses further comprise guardbands configured to prevent crosstalkbetween the wavelength sets caused by wavelength shifting from passagethrough one of the lenses at an angle of approximately 26 degrees. 10.The 3D viewing glasses according to claim 1, wherein the lenses furthercomprise guardbands configured to prevent crosstalk between thewavelength sets caused by wavelength shifting from passage through oneof the lenses at an angle of approximately greater than 20 degrees. 11.The 3D viewing glasses according to claim 1, wherein the lenses furthercomprise guardbands configured to prevent crosstalk between thewavelength sets caused by wavelength shifting from passage through oneof the lenses at an angle of approximately 40 degrees.
 12. The 3Dviewing glasses according to claim 1, wherein the lenses furthercomprise guardbands configured to prevent crosstalk between thewavelength sets caused by wavelength shifting from passage through oneof the lenses at an angle of between approximately 20 degrees and 40degrees.
 13. The 3D viewing glasses according to claim 1, wherein thelenses further comprise guardbands configured to prevent crosstalkbetween the wavelength sets caused by wavelength shifting from passagethrough one of the lenses at an angle of between approximately 26degrees and 40 degrees.
 14. 3D viewing glasses comprising a first lenscomprising a first set of passbands and a second lens comprising asecond set of passbands wherein the passbands are configured to passlight wavelengths comprising image content carrying wavelengthscomprising wavelengths projected from an image projection system andwavelengths projected from the image projection system and shifted,wherein the shifted wavelengths are blue shifted by an amount caused byangular passage through the lenses normally encountered in a cinematheater, and the lenses further comprise guard bands of sufficient widthto prevent passage by the second set of passbands of wavelengths shiftedfrom wavelengths that previously were within the first set of passbands.15. The 3D viewing glasses according to claim 14, wherein the shiftedwavelengths passed by the lenses comprise wavelengths shifted by up toapproximately a 20 degree angle of passage through one of the lenses.16. The 3D viewing glasses according to claim 15, wherein a curvature ofthe lenses is sufficient to cause wavelengths from a display screen tobe incident and/or pass the lenses at a maximum of approximately 20degrees to a normal of the lens surface.
 17. The 3D viewing glassesaccording to claim 14, wherein the content carrying wavelengths comprisewavelengths projected by a Dolby 3D cinema projection system.
 18. The 3Dviewing glasses according to claim 14, wherein the first set ofpassbands comprise passbands of approximately 425 nm to 455 nm, 490 nmto 530 nm, and 575 nm to 630 nm, and the second set of passbandscomprise passbands of approximately 460 nm to 475 nm, 540 nm to 570 nm,and 640 nm to 690 nm.
 19. The 3D viewing system according to claim 14,wherein the first set of passbands consisting of approximately 425 nm to455 nm, 490 nm to 530 nm, and 575 nm to 630 nm, and the second set ofpassbands consisting of approximately 460 nm to 475 nm, 540 nm to 570nm, and 640 nm to 690 nm.
 20. The 3D viewing glasses according to claim14, wherein guardbands of the lenses prevent passage of shiftedwavelengths intended to be passed by the other lens.
 21. The 3D viewingglasses according to claim 14, wherein the lenses prevent crosstalk ofwavelengths passing one of the lenses that were intended to be passed bythe other lens due to shifting caused by angular incidence of thewavelengths at an angle of approximately greater than 20 degrees. 22.The 3D viewing glasses according to claim 14, wherein the lenses preventcrosstalk of wavelengths passing one of the lenses that were intended tobe passed by the other lens due to shifting caused by angular incidenceof the wavelengths at an angle of approximately 40 degrees.
 23. The 3Dviewing glasses according to claim 14, wherein the lenses preventcrosstalk of wavelengths passing one of the lenses that were intended tobe passed by the other lens due to shifting caused by angular incidenceof the wavelengths at an angle of between approximately 20 degrees andapproximately 40 degrees.
 24. The 3D viewing glasses according to claim14, wherein the lenses prevent crosstalk of wavelengths passing one ofthe lenses that were intended to be passed by the other lens due toshifting caused by angular incidence of the wavelengths at an angle ofbetween approximately 26 degrees and 40 degrees.
 25. 3D viewing glassesincorporating lenses comprising a combination of spectrally separatedmutually exclusive passbands, lens curvature, and guard bands configuredto operate in concert with spectrally separated, pre-blue shifted, andcolor corrected image projections, the passbands comprising a first setof passbands comprising passbands of approximately 425 nm to 455 nm, 490nm to 530 nm, and 575 nm to 630 nm, and a second set of passbandscomprising passbands of approximately 460 nm to 475 nm, 540 nm to 570nm, and 640 nm to 690 nm.